1. Field of the Invention
The present invention relates to a novel process for producing allyl alcohol derivatives having the formula ##STR2## wherein R.sup.1 represents a hydrogen atom or a lower alkyl group, R.sup.2 represents an alkyl group which can have an inert substitutent, and X represents a hydrogen atom, or a hydroxy, an alkoxy, a tetrahydropyranyloxy or a silyloxy group; which are novel compounds and are useful intermediates for the syntheses of prostaglandins and analogous compounds which have excellent physiological activities and are useful medicines.
2. Description of the Prior Art
Heretofore, various precursors for producing prostaglandins have been proposed. Various intermediates having lactone and lactol structures have been used and the syntheses of prostaglandins have been reported. [E. J. Corey et al., Tetrahedron Lett., 4753 (1971); R. B. Woodward et al., J. Amer. Chem. Soc., 95, 6853 (1973); E. J. Corey et al., J. Org. Chem., 40, 2265 (1975); E. J. Corey et al., J. Amer. Chem. Soc., 91, 5675 (1969); E. J. Corey et al., ibid., 93, 1490 (1971); P. Crabbe et al., Tetrahedron Lett., 115 (1975); E. J. Corey et al., ibid., 3091 (1973); D. Brewster et al., Chem. Commun., 1235 (1972); J. Fried et al., Tetrahedron Lett., 3899 (1973); J. Fried et al., J. Amer. Chem. Soc., 94, 4342, 4343 (1972); E. J. Corey et al., Tetrahedron Lett., 311 (1970); R. C. Kelly et al., J. Amer. Chem. Soc., 95, 2746 (1973)].
These precursors and processes have many advantages. However, they also have the following disadvantages; the starting materials are not easily obtained, selectivities of the reactions used are poor, expensive reagents are needed in some cases, the conditions of the reactions are not easily controlled, and the purification of the products is not easy. In particular alkyl groups residing at higher than position 14 of the prostanoic acid skeleton have been mostly introduced by Wittig condensation as shown by the references cited above, and the processes are thus not economical.
The inventors have investigated a novel route to prostaglandins and analogs which is operable in industrial processes and have found the process for producing allyl alcohol derivatives having the formula (XI) which can be easily converted to prostaglandins and analogs.